ATmega64 Atmel Corporation, ATmega64 Datasheet - Page 35

• Manufacturer Part Number: ATmega64
• Manufacturer: Atmel Corporation

Specifications of ATmega64

• Flash (kbytes): 64 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 53
• Ext Interrupts: 8
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 8
• Input Capture Channels: 2
• Pwm Channels: 7
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Using all Locations of
External Memory
Smaller than 64
Kbytes
2490Q–AVR–06/10
Since the external memory is mapped after the internal memory as shown in
external memory is not addressed when addressing the first 4,352 bytes of data space. It may
appear that the first 4,352 bytes of the external memory are inaccessible (external memory
addresses 0x0000 to 0x10FF). However, when connecting an external memory smaller than 64
Kbytes, for example 32 Kbytes, these locations are easily accessed simply by addressing from
address 0x8000 to 0x90FF. Since the External Memory Address bit A15 is not connected to the
external memory, addresses 0x8000 to 0x90FF will appear as addresses 0x0000 to 0x10FF for
the external memory. Addressing above address 0x90FF is not recommended, since this will
address an external memory location that is already accessed by another (lower) address. To
the Application software, the external 32 Kbytes memory will appear as one linear 32 Kbytes
address space from 0x1100 to 0x90FF. This is illustrated in
refers to the ATmega103 compatibility mode, configuration A to the non-compatible mode.
When the device is set in ATmega103 compatibility mode, the internal address space is 4,096
bytes. This implies that the first 4,096 bytes of the external memory can be accessed at
addresses 0x8000 to 0x8FFF. To the Application software, the external 32 Kbytes memory will
appear as one linear 32 Kbytes address space from 0x1000 to 0x8FFF.
Figure 17. Address Map with 32 Kbytes External Memory
0x0000
0x10FF
0x1100
0x7FFF
0x8000
0x90FF
0x9100
0xFFFF
AVR Memory Map
Internal Memory
External
(Unused)
Memory
Memory Configuration A
External 32K SRAM
0x0000
0x10FF
0x1100
0x7FFF
0x0000
0x0FFF
0x1000
0x7FFF
0x8000
0x8FFF
0x9000
0xFFFF
AVR Memory Map
Internal Memory
External
(Unused)
Memory
Figure
Memory Configuration B
17. Memory configuration B
ATmega64(L)
External 32K SRAM
Figure
0x0000
0x0FFF
0x1000
0x7FFF
11, the
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